1. Field of the Invention
The present invention relates to an assembly for a motor vehicle, and more specifically to an assembly including a deflection element.
2. Description of Related Art
Managing deflection and movement of various vehicle components in a collision is one aspect of maintaining vehicle crashworthiness. Even in times of progressive restraint systems such as a belt tensioner or airbag, which are triggered on or, if applicable, immediately before an impact, it is desired to manage the deformation zone. The deformation zone is the region of the vehicle deformed on a collision, and therefore receiving energy. An effective deformation zone must not be too soft, because the deformation process reduces too little energy and allowing deformation of the passenger compartment. Rigid and stable components lead to higher, and under certain circumstances unacceptable accelerations, which act on the occupants. For example, the engine block, as a non-deformable body, likewise reduces the energy absorption through structural deformation. The deformation zone can extend over the front, the rear, and both sides of the vehicle.
Forming a reduced deformation zone in the front region of modern vehicles depends on various factors. On the one hand, owing to the increasingly more strict requirements regarding emissions and fuel consumption, the engine, the transmission and additional components take up an increasing amount of space; these components or respective assemblies are generally not deformable. Further, the size of the batteries is constantly increasing due to the growing number of electrical/electronic consumers. There is an increasing tendency to reduce the length of the structural vehicle front for reasons of weight and design. With the same energy input and structure, there follows a more intensive deformation of the firewall (i.e. the wall between engine and occupant), which consequently can shift the steering column and pedals toward the occupant.
A further restriction of the deformation zone results through brake force boosters. In brake systems with a brake force booster, normally the main brake cylinder forms an assembly with the brake force booster. The housing of the brake force booster is generally too weak to receive the forces occurring on the part of the main cylinder. The main cylinder is fastened on the vehicle side with one or more connecting members (also designated as connecting rods or tie rods), which are guided through the brake force booster. Each connecting rod forms in its axial direction a rigid component within the engine compartment, which typically does not deform and is directed toward the occupants. It has been found that deformation of the driver's compartment near the firewall at the height of the steering column originates principally from an interaction, i.e. a collision, either of the engine block, gear components, or the battery with a connecting rod of the brake force booster. However, it is difficult or respectively almost impossible, to prevent a contact of the said components with the connecting rod in a collision, without distinctly reducing the size (length/width) of the interacting components. Similar problems can also arise in other vehicle assemblies, for example tank connecting bolts during a rear impact or an interaction of fuel lines with bolts securing assemblies in a side impact, in which the axial rigidity of a connecting rod impairs the deformation behavior in a collision. They are not restricted to the front of the vehicle.